Conventionally, as a method for manufacturing a toroidal coil device employing a rectangular wire as a coil conductive wire, there has been proposed a method of, first, winding a conductive wire A around a round-shaft-like core B to form it in a shape of a coil as shown in FIG. 26(a), and thereafter, extracting the core B to make it an air core coil C as shown in FIG. 26(b), then subsequently, winding the air core coil C around a ring-like core D while transforming one end part of the air core coil C as shown in FIG. 26(c).
However, in the manufacturing method shown in FIG. 26, a rotational drive mechanism to wind the air core coil C around the ring-like core D as shown in FIG. 26(c) is complicated, and moreover, if transformation of the one end of the air core coil C exceeds an elastic deformation limit, subsequent winding step becomes extremely difficult.
Therefore, a manufacturing apparatus shown in FIGS. 23 and 24 is proposed (Japan Patent Laid-Open 2004-327461). This manufacturing apparatus includes a guide member 9 through which a conductive wire 21 passes, a pair of drive rollers 91, 91 which feed the conductive wire 21 in the guide member 9, and a forming member 7 for bending the conductive wire 21 fed from the guide member 9. By feeding the conductive wire 21 from the guide member 9, and at the same time pressing the conductive wire 21 against a forming surface 71 of the forming member 7, the apparatus bends the conductive wire 21 as indicated by a chain line in FIG. 25, and winds the conductive wire 21 around an outer peripheral surface of a core 1 as shown in FIGS. 23 and 24.